Practice?s

Question 1

All  of  the following  enzymes  involved  in the flow  of  carbon  from  glucose  to pyruvate are  also involved in the reversal of this flow except:  A)  3-phosphoglycerate kinase
B)  aldolase 
C)  enolase   
D)  phosphofructokinase-1 
E) phosphoglucoisomerase

Answer 1

D) phosphofructokinase-1

Question 2

2. During strenuous exercise, the NADH formed in the glyceraldehyde 3-phosphate dehydrogenase reaction in skeletal muscle must be reoxidized to NAD+ if glycolysis is to continue. The most important reaction involved in the reoxidation of NADH is:
   A) dihydroxyacetone phosphate ➡️glycerol 3-phosphate
   B) glucose 6-phosphate ➡️ fructose 6-phosphate
   C) pyruvate ➡️ lactate
   D) isocitrate ➡️ alpha-ketoglutarate
   E) oxaloacetate ➡️ malate

Answer 2

C) pyruvate ➡️ lactate

Question 3

The depicted compound is CH3COCOOH
A) an amino acid
B) a substrate of pyruvate kinase and pyruvate dehydrogenase
C) a product of pyruvate kinase
D) a product of pyruvate carboxylase
E) a citric acid cycle intermediate

Answer 3

C) a product of pyruvate kinase

Question 4

Glycogen conversion to monosaccharide units is an example of a  
A)  phosphomutase reaction   
B)  TPP-dependent  hexose  transfer 
C)  hydrolysis  reaction 
D)  phosphorolysis reaction 
E) gluconeogenesis reaction

Answer 4

D) phosphorolysis reaction

Question 5

The NAD+-requirement in galactose utlization occurs in a step in which
A) Galactose plus NAD+ is converted to glucose plus NADH
B) galactose is phosphorylated
C) the OH in the 4 position of free galactose is epimerized to form glucose
D) the OH in the 4 position of UDP-galactose is epimerized to form UDP-glucose
E) galactose-1-phosphate is converted to UDP-galactose

Answer 5

D) the OH in the 4 position of UDP-galactose is epimerized to form UDP-glucose

Question 6

The main function of the pentose phosphate pathway is to:
A) give the cell an alternative pathway should glycolysis fail
B) produce ribose-5-phosphate and NADPH
C) provide a mechanism for the utilization of the carbon skeletons of excess amino acids
D) produce ATP
E) produce NADH for use in oxidative phosphorylation

Answer 6

B) produce ribose-5-phosphate and NADPH

Question 7

Hexokinase
A) has the ability to mediate substrate level phosphorylation with glucose-6-phosphate as the phosphoryl donor
B ) has evolved to be saturated by glucose at extremely low glucose levels in liver
C) is encoded on a bifunctional enzyme with glucose 6-phosphatase
D) is encoded by different isozymes in different tissues
E) is localized in the endoplasmic reticulum

Answer 7

D) is encoded by different isozymes in different tissues

Question 8

Phosphofructokinase-1, which uses ATP to phosphorylate fructose-6-phosphate, is
A) positively regulated by ATP concentration
B) dependent on ATP but also activated by ADP
C) independently and positively controlled by fructose-6-phosphate and ATP concentrations
D) only limited by fructose-6-phosphate concentration
E) activated by glucose-6-phosphate

Answer 8

B) dependent on ATP but also activated by ADP

Question 9

Which of the following statements about gluconeogenesis in animal cells is true?
A) A rise in the cellular level of fructose-2,6-bisphosphate stimulates the rate of gluconeogenesis.
B) An animal fed a large excess of fat in the diet will convert any fat not needed for energy production into glycogen to be stored for later use.
C) ATP is regenerated by substrate-level phosphorylation during this process.
D) The conversion of pyruvate to phosphoenolpyruvate occurs in two steps, including a carboxylation.
E) The conversion of glucose 6-phosphate to glucose is catalyzed by hexokinase, the same enzyme involved in glycolysis.

Answer 9

D) The conversion of pyruvate to phosphoenolpyruvate occurs in two steps, including a carboxylation

Question 10

There is reciprocal regulation of glycolytic and gluconeogenic reactions interconverting fructose-6phosphate and fructose-1,6-bisphosphate. Which one of the following statements about this regulation is not correct? A) Fructose-2,6-bisphosphate activates phosphofructokinase-1.
B) Fructose-2,6-bisphosphate inhibits fructose-1,6-bisphosphatase.
C) Glucagon signaling promotes phosphofructokinase-1 activity.
D) Insulin signaling promotes phosphofructokinase-1 activity.
E) PFK2 and FBPase are on the same polypeptide

Answer 10

C) Glucagon signaling promotes phosphofructokinase-1 activity.

Question 11

Which of the following is true of glycogen synthesis and breakdown?
A) Phosphorylation activates the enzyme responsible for breakdown, and inactivates the synthetic enzyme.
B) Synthesis is catalyzed by the same enzyme that catalyzes breakdown.
C) The glycogen molecule “grows” at its reducing end.
D) The immediate product of glycogen breakdown is free glucose.
E) Under normal circumstances, glycogen synthesis and glycogen breakdown occur simultaneously and at high rates.

Answer 11

A) Phosphorylation activates the enzyme responsible for breakdown, and inactivates the synthetic enzyme

Question 12

The metabolic flux for an enzyme-catalyzed step in a multistep pathway depends on:
A) the concentration of the enzyme itself.
B) the concentration of other enzymes in the pathway.
C) the levels of regulatory molecules.
D) the amounts of substrate molecules present at each step.
E) all of the above.

Answer 12

E) all of the above

Question 13

The elasticity of an enzyme is maximized
A) well above substrate Km
B) below substrate Km
C) when an enzyme is regulated transcriptionally
D) when an enzyme is regulated by proteolysis
E) when an enzyme is regulated allosterically

Answer 13

C) when an enzyme is regulated transcriptionally

Question 14

Which of the below is not required for the oxidative decarboxylation of pyruvate to form acetyl-CoA?  
A) Flavin
B)  C8S2H14
C)  NAD+   
D)  TPP 
E) FAD

Answer 14

A) Flavin

Question 15

Which of the following is not an intermediate of the citric acid cycle?  
A)  Phosphoenolpyruvate 
B)  Citrate   
C)  Oxaloacetate   
D)  Succinyl-coA   
E) alpha-Ketoglutarate

Answer 15

A) Phosphoenolpyruvate

Question 16

The  reaction of  the citric  acid cycle  that produces  an ATP  equivalent (in the  form of GTP) by substrate level phosphorylation is the conversion of: 
A)  citrate  to isocitrate 
B)  fumarate  to malate
C) malate to  oxaloacetate 
D)  succinate  to fumarate 
E) succinyl-CoA to succinate

Answer 16

E) succinyl-CoA to succinate

Question 17

For the following reaction, 🔼G’° = 29.7 kJ/mol. L-Malate + NAD+ ➡️ oxaloacetate + NADH + H+ The reaction as written:
A) cannot occur in a cell in the indicated direction
B) can only occur in a cell if it is coupled to another reaction for which 🔼G’° is positive.
C) can only occur in a cell in which NADH is converted to NAD+ by electron transport.
D) can occur in a manner linked to the availability of acetyl-coA
E) would always proceed at a very slow rate

Answer 17

D) can occur in a manner linked to the availability of acetyl-coA

Question 18

All of the oxidative steps of the citric acid cycle are linked to the reduction of NAD+ except the reaction catalyzed by:
A) isocitrate dehydrogenase, which is part of the electron transport chain B) malate dehydrogenase, which is part of the electron transport chain
C) pyruvate dehydrogenase, which is part of the electron transport chain
D) succinate dehydrogenase, which is part of the electron transport chain
E) the a-ketoglutarate dehydrogenase complex, which is part of the electron transport chain

Answer 18

D) succinate dehydrogenase, which is part of the electron transport chain

Question 19

If there is no acetyl-coA in mitochondria and a good supply of GTP, oxaloacetate can be used to form
A) pyruvate for gluconeogenesis
B) alanine
C) phosphoenolpyruvate for gluconeogenesis
D) reduced co-factors for the electron transport chain
E) purines

Answer 19

C) phosphoenolpyruvate for gluconeogenesis

Question 20

In amino acid catabolism, the first reaction for many amino acids is a:
A) decarboxylation requiring thiamine pyrophosphate (TPP)
B) hydroxylation requiring NADPH and O2
C) oxidative deamination requiring NAD+
D) reduction requiring pyridoxal phosphate (PLP)
E) transamination requiring pyridoxal phosphate (PLP)

Answer 20

E) transamination requiring pyridoxal phosphate (PLP)

Question 21

In the transamination reaction in which oxaloacetate is converted to aspartate,
A) Pb is converted to Au
B) NAD+ is converted to NADH
C) Glutamate is converted to α-ketoglutarate
D) α-ketoglutarate is converted to glutamate
E) ATP is produced with liberation of NH4+

Answer 21

C) Glutamate is converted to α-ketoglutarate

Question 22

The enzyme which catalyzes the reaction depicted above is: 
A) Glutaminase 
B) Glutamate aminotransferase 
C) Glutamate dehydrogenase 
D) Glutamine:  NAD(P)+ reductase 
E)  α-ketogluterate aminomutase

Answer 22

C) Glutamate dehydrogenase

Question 23

23. In the middle of digesting a hamburger, what would be the anticipated consequences of ingesting an inhibitor of the enzyme, which catalyzes the reaction depicted above question 22:
    A) inability to catabolize most amino acids
    B) shut down of the citric acid cycle
    C) decreased production of carbamoyl phosphate
    D) B & C
    E) all of the above

Answer 23

A) inability to catabolize most amino acid

Question 24

Which of these directly donates a nitrogen atom for the formation of urea during the urea cycle?  
A)  Adenine   
B)  Aspartate   
C)  Creatine   
D)  Glutamate   
E)  Ornithine

Answer 24

B) Aspartate

Question 25

Ingestion of a carbamoyl phosphate synthase inhibitor would be most toxic in a meal of: 
A)  Starch 
B)  Sugar 
C)  Protein 
D)  Fatty  acids 
E) phospholipids

Answer 25

C) Protein

Question 26

The amino acids serine, alanine, and cysteine can be catabolized to yield:  
A)  fumarate 
B)  pyruvate   
C)  succinate   
D)  a-ketoglutarate   
E) none of the above

Answer 26

B) pyruvate

Question 27

In the glucose alanine cycle,
A) Liver releases alanine for the muscle to produce glucose
B) Liver releases glucose for the brain to produce alanine
C) Liver and muscle use alanine aminotransferase in the same direction in response to the fed state
D) Liver performs gluconeogenesis with carbons that were derived from muscle protein E) Muscle performs gluconeogenesis with carbons that were derived from liver protein

Answer 27

D) Liver performs gluconeogenesis with carbons that were derived from muscle protein

Question 28

Whereas cytoplasmic NADPH is primarily used for reductive biosynthesis of sterols, mitochondrial NADH is primarily used for
A) reductive biosynthesis of mitochondrial lipids
B) reductive biosynthesis of mitochondrial ATP
C) electron transfer linked to generation of a proton gradient, which produces ATP using a rotary enzyme
D) electron transfer to ATP synthase, which uses the electrons to catalyze formation of ATP from ADP plus phosphate
E) electron transfer to the cytochrome complexes, which allosterically activate ATP synthase

Answer 28

C) electron transfer linked to generation of a proton gradient, which produces ATP using a rotary enzyme

Question 29

The malate-aspartate shuttle
A) uses the same enzymes on different sides of the mitochondrial inner membrane to maintain a high NADH/NAD+ ratio in the mitochondrial matrix
B) transports nonphosphorylated compounds in and out of the mitochondrial matrix with the net result of effecting the redox state of phosphorylated compounds that are not transported
C) can accelerate glycolytic and oxidative phosphorylation simultaneously
D) A and B
E) A, B and C

Answer 29

D) A and B

Question 30

Cytoplasmically produced NADH
A) Donates electrons to Q in the mitochondrial inner membrane
B) Can contribute to the electron transport chain by reduction of FAD and subsequent reduction of Q
C) Goes through the malate aspartate shuttle and is used by complex 1 D) Is disposed in the urea cycle
E) Can contribute to respiration when mitochondria are treated with an uncoupling reagent

Answer 30

B) Can contribute to the electron transport chain by reduction of FAD and subsequent reduction of Q

Question 31

The photosynthetic reaction center
A) Chemically reacts with a water derived electron such that it can reduce Q, flow through a cytochrome B-type complex, and produce a proton gradient
B) Elevates the energy state of a water derived photon so that it can reduce NADP to NADPH
C) Uses two photons to elevate the energy state of a water derived electron in reactions linked to proton pumping and NADP reduction
D) Uses CO2 to reduce NADP to NADPH and a photon gradient to run ATP synthase
E) Uses one photon to elevate the energy state of two water derived electrons that drive ATP synthase and NADPH formation

Answer 31

C) Uses two photons to elevate the energy state of a water derived electron in reactions linked to proton pumping and NADP reduction

Question 32

In mitochondria, the rate of ATP formation depends on
A) Continuous resupply of ADP and phosphate
B) Flux through the Q cycle
C) Proton pores to dissipate the proton gradient
D) A and B
E) All of the above

Answer 32

E) All of the above

Question 33

During oxidative phosphorylation, the proton motive force that is generated by electron transport is used to:
A) create a pore in the inner mitochondrial membrane.
B) catalyze ATP release by ATP synthase
C) perform a difficult substrate level phosphorylation
D) oxidize NADH to NAD+
E) reduce O2 to H2O

Answer 33

B) catalyze ATP release by ATP synthase

Question 34

During strenuous exercise, the NADH formed in the glyceraldehyde 3-phosphate dehydrogenase reaction in skeletal muscle must be reoxidized to NAD+ if glycolysis is to continue. Apart from fermentation, how can cytosolic NADH be reoxidized to NAD+
A) Pyruvate is reduced to lactate
B) Pyruvate is oxidized to lactate
C) Reducing equivalents from NADH can be converted to FADH2 on the mitochondrial inner membrane
D) Pyruvate is converted to ethanol
E) Pyruvate is converted to alanine

Answer 34

C) Reducing equivalents from NADH can be converted to FADH2 on the mitochondrial inner membrane

Question 35

The committed steps of glycolysis is catalyzed by  
A)  hexokinase
B)  phosphohexose isomerase   
C)  phosphofructokinase 1   
D)  phosphofructokinase 2 
E) aldolase

Answer 35

C) phosphofructokinase 1

Question 36

Which of the following compounds would produce the most glucose at the least expense of ATP?  
A)  Ac-coA   
B)  alanine 
C)  glycine 
D)  pyruvate   
E) aspartic acid

Answer 36

E) aspartic acid

Question 37

The bypass enzyme for phosphofructokinase 1 is
A) Phosphofructokinase 2
B) Active when stimulated by insulin
C) Active when stimulated by glucagon
D) Capable of forming ATP from ADP and fructose-1-6-bisphosphate
E) phosphoglucoisomerase.

Answer 37

C) Active when stimulated by glucagon

Question 38

The bypass enzyme for phosphofructokinase 1 is
A) Phosphofructokinase 2
B) Active when stimulated by insulin
C) Active when stimulated by glucagon
D) Capable of forming ATP from ADP and fructose-1-6-bisphosphate
E) phosphoglucoisomerase.

Answer 38

C) Active when stimulated by glucagon

Question 39

The committed step of the pentose phosphate pathway is
A) Dependent on NADP and inhibited by NADPH
B) Dependent on TPP and inhibited by FADH2
C) Dependent on NAD and inhibited by NADH
D) Dependent on Ac-coA and inhibited by free coA
E) Dependent on oxygen and inhibited by FCCP

Answer 39

A) Dependent on NADP and inhibited by NADPH

Question 40

The above reaction occurs in which pathway
A) glycolysis
B) Leloir pathway for utilization of galactose
C) citric acid cycle
D) nonoxidative phase of the pentose phosphate pathway
E) urea cycle

Answer 40

D) nonoxidative phase of the pentose phosphate pathway

Question 41

NADPH generated in the mitochondrial matrix can be used for what purposes
A) running the pentose phosphate pathway B) detoxifying cytosolic reactive oxygen species
C) generating a proton motive force if it first encounters the nicotinamide nucleotide transhydrogenase
D) helping malate dehydrogenase work in the oxidizing direction
E) allosterically activating isocitrate dehydrogenase

Answer 41

C) generating a proton motive force if it first encounters the nicotinamide nucleotide transhydrogenase

Question 42

Which of the following statements about gluconeogenesis in animal cells is false?
A) Fatty acids are an excellent source of glucose through action of pyruvate carboxylase
B) It occurs simultaneously with glycogen breakdown
C) Some of the carbon from an amino acid that is ketogenic can also be glucogenic
D) Phosphoenolpyruvate carboxykinase is transcriptionally upregulated to facilitate it
E) It depends on glyceraldehyde-3-phosphate dehydrogenase and NADH

Answer 42

A) Fatty acids are an excellent source of glucose through action of pyruvate carboxylase

Question 43

An organism is discovered that can utilize galactose but does not have galactokinase, galactose-1-Puridylyltransferase or UDP-galactose epimerase. Speculate on the novel enzyme found in this organism.
A) It has a phosphogalactose mutase that converts galactose to glucose-6-phosphate B) It has a uridylyltransferase that uses galactose rather than galactose-6-phosphate C) It has a different pentose phosphate pathway that starts with galactose
D) It has an enzyme that can epimerize galactose to glucose
E) It has a relaxed specificity hexokinase that phosphorylates glucose and galactose

Answer 43

D) It has an enzyme that can epimerize galactose to glucose

Question 44

Which of the following is true of insulin signaling
A) The insulin receptor is coupled to adenylyl cyclase
B) Insulin is released by pancreatic alpha cells when glucose levels are high
C) There is no way to increase net glucose entry into cells because glucose can go in and out of the same facilitative transporters D) Phosphoprotein phosphatase 1 amplifies the glucagon signaling cascade
E) It leads to increased pyruvate kinase activity

Answer 44

E) It leads to increased pyruvate kinase activity

Question 45

If citric acid cycle intermediates are drawn off for anapleurotic reactions
A) all of the citric acid cycle enzymes become inhibited because of a concept termed coupling
B) metabolites can enter the cycle at one point and leave at another point with reasonable flux
C) glucose metabolism can provide carbons for both substrates of citrate synthase
D) heat is generated
E) both B and C.

Answer 45

E) both B and C.

Question 46

Flavoenzymes
A) Contain flavin nucleotide cofactors that diffuse to co-enzyme Q when they are in reduced form
B) Can be reoxidized by reduction of NAD+ or co-enzyme Q
C) Always contain a lipoic acid co-factor
D) Always cleave alpha to a keto group
E) Always do one carbon transfer

Answer 46

B) Can be reoxidized by reduction of NAD+ or co-enzyme Q

Question 47

Arginosuccinate is an intermediate in the
A) Glycolysis
B) Citric Acid Cycle C) Glucose-Alanine cycle
D) Urea cycle
E) Glucagon-Hans Krebs porphirin cycle

Answer 47

D) Urea cycle

Question 48

Respiration-coupled activities of succinate dehydrogenase and NADH dehydrogenase result in
A) The same amount of ATP production because both initiate reactions that result in a coenzyme Q redox cycle
B) Lower ATP production by NADH dehydrogenase because its proton-pumping activity has to be paid for by ATP
C) Higher ATP production by NADH dehydrogenase because electron transfer from complex II bypasses protons pumpted by complex I
D) Higher ATP production by NADH dehydrogenase because it is directly linked to oxygen consumption
E) None of the above

Answer 48

C) Higher ATP production by NADH dehydrogenase because electron transfer from complex II bypasses protons pumpted by complex I

Question 49

For Asp to contribute an amino group to the urea cycle
A) Aspartate aminotransferase has to be inhibited
B) Aspartate amino transferase has to pick up amino groups from glutamate
C) Aspartate amino transferase has to liberate free ammonia
D) Aspartate amino transferase consumes ATP to AMP
E) Aspartate amino transferase consumes bicarbonate

Answer 49

B) Aspartate amino transferase has to pick up amino groups from glutamate

Question 50

A drug that inhibits complex III of the electron transfer chain would A) block most NADH reoxidation in mitochondria
B) block succinate oxidation and the coenzyme Q redox cycle
C) block formation of the pH gradient across the inner mitochondrial enzyme
D) block production of ATP production by FoF1 ATP synthase
E) all of the above

Answer 50

E) all of the above

Question 51

In amino acid catabolism, the first reaction for many amino acids:
A) Liberates ammonia and generates an alpha-keto acid
B) Generates either NADH or NADPH
C) A and B
D) Only occurs when glucagon signaling occurs
E) Requires a supply of alpha-ketoglutarate

Answer 51

E) Requires a supply of alpha-ketoglutarate

Question 52

In the transamination reaction in which alanine is converted to pyruvate,
A) The nitrogen is converted to carbamoyl phosphate
B) Free ammonia is produced
C) α-ketoglutarate is converted to glutamate
D) NAD+ is converted to NADH
E) Glutamate is converted to α-ketoglutarate

Answer 52

E) Glutamate is converted to α-ketoglutarate

Question 53

An enzyme called adenylate kinase can convert an AMP and ATP to two ADPs. This activity explains why
A) A GTP is equivalent to an ATP
B) Substrate level phosphorylation is less effective than oxidative phosphorylation C) Glucose-6 phosphatase is localized to the endoplasmic reticulum
D) Carbamoyl phosphate synthase effectively uses two ATPs
E) all of the above

Answer 53

D) Carbamoyl phosphate synthase effectively uses two ATPs

Question 54

Fumarate released from the urea cycle
A) Can be converted to oxaloacetate and Asp with production of NADH
B) Can be converted to oxaloacetate and Asp with production of free ammonia
C) Can be converted to oxaloacetate and Asp with production of FADH2 and free ammonia
D) Must be disposed in a 1:1 ratio with urea
E) Is at a higher energy state than the product of succinate dehydrogenase because it did not interact with coenzyme Q

Answer 54

A) Can be converted to oxaloacetate and Asp with production of NADH

Question 55

Uncoupling reagents allow mitochondria to produce heat by A) Increasing ATP production per input reducing equivalent
B) Capturing electrons that would otherwise go up in smoke
C) Creating a leak through the inner mitochondrial membrane that dissipates the proton gradient
D) Turning ATP synthase in the opposite direction
E) Binding to cytochrome oxidase and increasing its activity

Answer 55

C) Creating a leak through the inner mitochondrial membrane that dissipates the proton gradient

Question 56

Fuel broken down to acetyl coA A) Is glucogenic by virtue of transit through the citric acid cycle
B) Is not glucogenic because it requires an oxaloacetate to make an oxaloacetate
C) Is neither glucogenic nor ketogenic
D) Is simultaneously glucogenic and ketogenic
E) Is the most glucogenic carbon of all because it does not require the citric acid cycle to form phosphoenolpyruvate

Answer 56

B) Is not glucogenic because it requires an oxaloacetate to make an oxaloacetate

Question 57

A liver cell producing urea
A) Must oxidize pyruvate to produce the central carbon
B) Must have a high supply of glutamine to produce one of the urea nitrogens
C) Has amino acid aminotransferases and alpha-ketoglutarate
D) A and B
E) Can produce urea without satisfying any of the above conditions

Answer 57

C) Has amino acid aminotransferases and alpha-ketoglutarate

Question 58

The oxidative phase of the pentose phosphate pathway is connected to glycogen phosphorolysis by  
A) Glucose-6-phosphate dehydrogenase 
B)  6-phosphogluconate dehydrogenase 
C)  phosphoglucomutase 
D) triose  phosphate isomerase 
E) phosphofructokinase 1

Answer 58

C) phosphoglucomutase

Question 59

The malate-aspartate shuttle
A) uses a proton gradient to move aspartate into the cytoplasm for protein synthesis
B) uses the same enzymes on different sides of the mitochondrial inner membrane to transfer reducing equivalents across the inner mitochondrial enzyme
C) uses complexes I, III and IV to maintain an electrochemical gradient of malate and aspartate
D) produces a net change in the cellular redox state
E) uses ATP to maintain an electrochemical gradient of malate and aspartate

Answer 59

B) uses the same enzymes on different sides of the mitochondrial inner membrane to transfer reducing equivalents across the inner mitochondrial enzyme

Question 60

Cytoplasmically produced NADH A) Is interchangeable for ATP in the cytosol
B) Is exported with lactate in a process termed fermentation
C) Has a different structure than mitochondrial NADH
D) Can contribute to respiration through glycerol-3-phosphate redox reactions
E) can contribute to respiration when mitochondria are treated with an uncoupling reagent

Answer 60

D) Can contribute to respiration through glycerol-3-phosphate redox reactions

Question 61

Phosphohexose isomerase
A) Undergoes a conformational change to “know” whether it is engaged in glycolysis or gluconeogenesis
B) Is the committed step in both glycolysis and gluconeogenesis
C) Is regulated by insulin signaling
D) Is regulated by glucagon signaling
E) Net rate is determined by the rate of upstream and downstream reactions

Answer 61

E) Net rate is determined by the rate of upstream and downstream reactions

Question 62

In normal brown fat, expression of an uncoupling protein
A) Allows continuous production of ATP even when there is no oxygen
B) Reduces ATP yield from respiration
C) Increases O2 consumption per unit of fuel consumed
D) Is blocked by glucagon signaling
E) Is blocked by insulin signaling

Answer 62

B) Reduces ATP yield from respiration

Question 63

During oxidative phosphorylation, the proton motive force that is generated by electron transport is used to:
A) Change the free energy of ATP formation
B) Position co-enzyme Q for its redox cycles
C) oxidize NADH to NAD+
D) Suppress reactive oxygen species formation E) None of the above

Answer 63

E) None of the above